Parametric DRAG for leakage-suppressed exchange gates in superconducting qubits

Abstract

Programmable exchange interactions support quantum gates and many-body simulation in superconducting circuits. Fast excitation transfer, however, opens two leakage pathways in weakly anharmonic transmons, degrading gates and driving simulated dynamics outside the encoded state space. We introduce parametric derivative removal by adiabatic gate (PDRAG) to suppress both pathways while preserving the target exchange. Their conjugate structure determines first- and second-derivative corrections implemented through one real frequency command. At $g/2π=100$ MHz, calibrated PDRAG achieves a geometric-mean leakage reduction of $5.27\times10^5$ relative to the base pulse across 12.5--35 ns in Duffing simulations. At 13 ns, endpoint leakage reaches $1.98\times10^{-7}$ for the calibrated full-exchange pulse. Transferring the derivative coefficients to a charge Hamiltonian gives a mean 893-fold reduction over 12.5--22 ns after amplitude and carrier recalibration. Floquet return interference and charge-induced gap shifts explain the calibration and transfer gains, connecting compact pulse design to leakage-suppressed programmable interactions.